Control system for automatic transmission

Claim 2

In an automatic automotive vehicle transmission used for transmitting torque between a driving shaft and a driven shaft, a control system comprising: frictional engaging means provided with fluid pressure operated servo means for selective actuation thereof and arranged for the transmission of torque between said driving and driven shafts, a source of fluid pressure for supplying fluid under pressure for actuating said frictional engaging means by selective application to said servo means, fluid passage means leading from said fluid pressure source to said frictional engaging means, fluid passage change-over valve means disposed in said fluid passage means for selectively distributing fluid under pressure to predetermined servo means in said frictional engaging means, signal generator means including a signal generator for generating a first electrical signal responsive to at least one of the running conditions of the vehicle, fluid pressure control means for controlling the pressure of fluid supplied to said frictional engaging means through said fluid passage change-over valve means, and timing control means for generating a second electrical signal and means for controlling the operation timing of said fluid pressure control means in response to the first electrical signal delivered from said signal generator means, whereby said fluid pressure control means is subject to on-off control during a shift from one gear position to another which is followed by a variation in the torque being transmitted between said driving and driven shafts so as to control the fluid pressure supplied to said frictional engaging means thereby ensuring smooth transmission of the torque between said driving and driven shafts during the shift.

Claim 3

In an automatic automotive vehicle transmission used for transmitting torque between a driving shaft and a driven shaft, a control system comprising: frictional engaging means provided with fluid pressure operated servo means for selective actuation thereof and arranged for the transmission of torque between said driving and driven shafts, a source of fluid pressure for supplying fluid under pressure for actuating said frictional engaging means by selective application to said servo means, fluid passage means leading from said fluid pressure source to said frictional engaging means, shift valve means disposed in said fluid passage means for selectively distributing fluid under pressure to predetermined servo means in said frictional engaging means, means for generating an electrical signal responsive to the engine torque, means for generating an electrical signal responsive to the vehicle speed, shift signal computing means for computing the relation between these two electRical signals and for generating a shift signal when the relation between these two signals satisfies a predetermined condition, fluid pressure supply control valve means for allowing leakage of fluid under pressure in said fluid passage means leading to said frictional engaging means through said shift valve means thereby controlling the fluid pressure supplied to said frictional engaging means, and timing control means for generating a timing control signal in response to the output signal delivered from said shift signal computing means for controlling the period of time of the leakage of fluid under pressure from said fluid passage means through said fluid pressure supply control valve means, whereby said fluid pressure supply control valve means controls the rate of increase or decrease relative to time of the pressure of fluid supplied to said frictional engaging means for ensuring smooth transmission of the torque between said driving and driven shafts during a shift from one gear position to another.

Claim 4

In an automatic automotive vehicle transmission used for transmitting torque between a driving shaft and a driven shaft, a control system comprising: frictional engaging means provided with fluid pressure operated servo means for selective actuation thereof and arranged for the transmission of torque between said driving and driven shafts, a source of fluid pressure for supplying fluid under pressure for actuating said frictional engaging means by selective application to said servo means, fluid passage means leading from said fluid pressure source to said frictional engaging means, shift valve means disposed in said fluid passage means for selectively distributing fluid under pressure to predetermined servo means in said frictional engaging means, means for generating an electrical signal responsive to the engine torque, means for generating an electrical signal responsive to the vehicle speed, shift signal computing means for computing the relation between these two electRical signals and for generating a shift signal when the relation between these two signals satisfies a predetermined condition, fluid pressure supply control valve means for allowing leakage of fluid under pressure in said fluid passage means leading to said frictional engaging means through said shift valve means thereby controlling the fluid pressure supplied to said frictional engaging means, and timing control means for generating a timing control signal in response to the output signal delivered from said shift signal computing means for controlling the period of time of the leakage of fluid under pressure from said fluid passage means through said fluid pressure supply control valve means, whereby said fluid pressure supply control valve means controls the rate of increase or decrease relative to time of the pressure of fluid supplied to said frictional engaging means for ensuring smooth transmission of the torque between said driving and driven shafts during a shift from one gear position to another.

Claim 5

In an automatic automotive vehicle transmission used for transmitting torque between a driving shaft and a driven shaft, a control system comprising: a first frictional engaging means provided with a fluid pressure operated servo means for establishing a high speed drive ratio between said drivingand driven shafts, a second frictional engaging means provided with a fluid pressure operated servo means having an apply-side chamber and a release-side chamber for establishing a low speed drive ratio between said driving and driven shafts, a source of fluid pressure for supplying fluid under pressure for actuating said frictional engaging means, a plurality of shift valves for selectively distributing fluid under pressure to said frictional engaging means, a first fluid passage leading from one of said shift valves to the apply-side chamber of said fluid pressure operated servo means for said second frictional engaging means, a second fluid passage leading from another said shift valve to the fluid pressure operated servo means for said first frictional engaging means and to the release-side chamber of said fluid pressure operated servo means for said second frictional engaging means, a fluid pressure supply control valve connected to said first and second fluid passages for connecting and disconnecting the apply-side servo chamber with the release-side servo chamber with the release-side servo chamber of said fluid pressure operated servo means for said second frictional engaging means thereby controlling the fluid pressure supplied to said second frictional engaging means, signal generator means including a signal generator for generating an electrical signal responsive to at least one of the running conditions of the vehicle, and timing control means for generating a timing control signal for controlling the operation timing of said fluid pressure supply control valve in response to the output signal delivered from said signal generator means, whereby said fluid pressure supply control valve controls the fluid pressure supplied to both of said frictionally engaging means during a shift from one gear position to another which is followed by a variation in the drive ratio between said driving and driven shafts so as to ensure a smooth transition from one gear position to another.

Claim 6

In an automatic automotive vehicle transmission used for transmitting torque between a driving shaft and a driven shaft, a control system comprising: a first frictional engaging means provided with a fluid pressure operated servo means for establishing a high speed drive ratio between said drivingand driven shafts, a second frictional engaging means provided with a fluid pressure operated servo means having an apply-side chamber and a release-side chamber for establishing a low speed drive ratio between said driving and driven shafts, a source of fluid pressure for supplying fluid under pressure for actuating said frictional engaging means, a plurality of shift valves for selectively distributing fluid under pressure to said frictional engaging means, a first fluid passage leading from one of said shift valves to the apply-side chamber of said fluid pressure operated servo means for said second frictional engaging means, a second fluid passage leading from another said shift valve to the fluid pressure operated servo means for said first frictional engaging means and to the release-side chamber of said fluid pressure operated servo means for said second frictional engaging means, a fluid pressure supply control valve connected to said first and second fluid passages for connecting and disconnecting the apply-side servo chamber with the release-side servo chamber with the release-side servo chamber of said fluid pressure operated servo means for said second frictional engaging means thereby controlling the fluid pressure supplied to said second frictional engaging means, signal generator means including a signal generator for generating an electrical signal responsive to at least one of the running conditions of the vehicle, and timing control means for generating a timing control signal for controlling the operation timing of said fluid pressure supply control valve in response to the output signal delivered from said signal generator means, whereby said fluid pressure supply control valve controls the fluid pressure supplied to both of said frictionally engaging means during a shift from one gear position to another which is followed by a variation in the drive ratio between said driving and driven shafts so as to ensure a smooth transition from one gear position to another.

Claim 7

In an automatic automotive vehicle transmission used for transmitting torque between a driving shaft and a driven shaft, a control system comprising: a first frictional engaging means provided with a fluid pressure operated servo means for establishing a high speed drive ratio between said driving and driven shafts, a second frictional engaging means provided with a fluid pressure operated servo means having an apply-side chamber and a release-side chamber for establishing a low speed drive ratio between said driving and driven shafts, a source of fluid pressure for supplying fluid under pressure for actuating said friCtional engaging means, a plurality of shift valves for selectively distributing fluid under pressure to said frictional engaging means, a first fluid passage leading from one of said shift valves to the apply-side chamber of said fluid pressure operated servo means for said second frictional engaging means, a second fluid passage leading from another said shift valve to the fluid pressure operated servo means for said first frictional engaging means and to the release-side chamber of said fluid pressure operated servo means for said second frictional engaging means, an electromagnetically operated fluid pressure control valve connected with at least one of said first and second fluid passages for allowing leakage of fluid under pressure in said fluid passage, signal generator means including a signal generator for generating an electrical signal responsive to at least one of the running conditions of the vehicle, and timing control means for generating a timing control signal for controlling the operation timing of said electromagnetically operated fluid pressure control valve in response to the output signal delivered from said signal generator means, whereby said electromagnetically operated fluid pressure control valve controls the fluid pressure supplied to said frictional engaging means during a shift from one gear position to another which is followed by a variation in the drive ratio between said driving and driven shafts so as to ensure a smooth transition from one gear position to another.

Claim 8

In an automatic automotive vehicle transmission used for transmitting torque between a driving shaft and a driven shaft, a control system comprising: a first frictional engaging means provided with a fluid pressure operated servo means for establishing a high speed drive ratio between said driving and driven shafts, a second frictional engaging means provided with a fluid pressure operated servo means having an apply-side chamber and a release-side chamber for establishing a low speed drive ratio between said driving and driven shafts, a source of fluid pressure for supplying fluid under pressure for actuating said friCtional engaging means, a plurality of shift valves for selectively distributing fluid under pressure to said frictional engaging means, a first fluid passage leading from one of said shift valves to the apply-side chamber of said fluid pressure operated servo means for said second frictional engaging means, a second fluid passage leading from another said shift valve to the fluid pressure operated servo means for said first frictional engaging means and to the release-side chamber of said fluid pressure operated servo means for said second frictional engaging means, an electromagnetically operated fluid pressure control valve connected with at least one of said first and second fluid passages for allowing leakage of fluid under pressure in said fluid passage, signal generator means including a signal generator for generating an electrical signal responsive to at least one of the running conditions of the vehicle, and timing control means for generating a timing control signal for controlling the operation timing of said electromagnetically operated fluid pressure control valve in response to the output signal delivered from said signal generator means, whereby said electromagnetically operated fluid pressure control valve controls the fluid pressure supplied to said frictional engaging means during a shift from one gear position to another which is followed by a variation in the drive ratio between said driving and driven shafts so as to ensure a smooth transition from one gear position to another.

Claim 9

A control system for an automatic transmission as in claim 1, in which said fluid pressure control means comprises: an electromagnetically operated valve allowing leakage of fluid under pressure in said fluid passage means, and a valve for regulating the pressure of fluid, said electromagnetically operated valve and said fluid pressure regulating valve cooperating to control the fluid pressure supplied to said frictional engaging means.

Claim 10

A control system for an automatic transmission as in claim 1, in which said fluid pressure control means comprises: an electromagnetically operated valve for draining fluid in said fluid passage means, and an orifice control valve, said electromagnetically operated valve and said orifice control valve cooperating to control the fluid pressure supplied to said frictional engaging means.

Claim 11

In a control system for an automatic transmission comprising a plurality of frictional engaging means, each having fluid control means associated therewith for selectively effecting shift changes in torque transmitted between a driving and a driven shaft, an improvement comprising: fluid pressure modifying means for modulating normal selective changes in the fluid pressure applied to said fluid control means to effect desired shift changes in transmitted torque, and control means connected to said fluid pressure modifying means for controlling the timing and degree of modulation to effect a smooth change in the transmitted torque through said transmission during said desired shift changes.

Claim 12

In a control system for an automatic transmission comprising a plurality of frictional engaging means, each having fluid control means associated therewith for selectively effecting shift changes in torque transmitted between a driving and a driven shaft, an improvement comprising: fluid pressure modifying means for modulating normal selective changes in the fluid pressure applied to said fluid control means to effect desired shift changes in transmitted torque, and control means connected to said fluid pressure modifying means for controlling the timing and degree of modulation to effect a smooth change in the transmitted torque through said transmission during said desired shift changes.

Claim 13

improvement as in claim 7 wherein: said fluid pressure modifying means comprises at least one controllably opened or closed valve in fluid communication between a fluid passage having low fluid pressure during a given shift change and at least one fluid passage leading to a fluid control means having high pressure applied thereto for effecting said given shift, the rate of increase of pressure in said at least one fluid passage being effectively controllable by opening and closing said valve in response to an applied timing control signal, and said control means comprises means for detecting an impending shift change and for generating said timing control signal having a predetermined timing and duration with respect to the shift change being effected.

Claim 14

An improvement as in claim 8 wherein said valve comprises an orifice and means for closing and opening said orifice eleCtromagnetically.

Claim 15

An improvement as in claim 8 wherein said valve comprises a pressure regulating valve and associated means for effecting electromagnetic control thereof.

Claim 16

An improvement as in claim 8 wherein said valve is connected between fluid passages leading to two different ones of said fluid control means.